The present invention relates to an internal combustion engine with a crankcase, in which a crankshaft is mounted in a rotatable manner.
An internal combustion engine is disclosed in DE 44 24 248 C1. The oil is pumped over pressurized channels, running inside the walls of the cylinder head, and the adjoining longitudinal channels to air/oil separating elements inside the crankcase, in order to separate the air from the oil, flowing back into the oil pan. This separation of the air from the oil maintains the quality of the oil and guarantees that the internal combustion engine will operate reliably. However, the drawback with this feature is high casting complexity in producing the relatively long channels, the high space requirement, and the high power output required to circulate the oil and to separate the air from the oil.
DE 40 01 468 A1 describes an oil guide housing for an internal combustion engine, in which there are oil lathes, constructed as ribs, with which the oil is planed off from the figure eight-shaped connecting rod and is returned over the return channels into the oil pan. Yet this prior art design does not make it possible to separate the air from the oil returned to the oil pan.
Therefore, an object of the present invention is to provide an internal combustion engine, in which the oil is returned to the oil pan as fast as possible and with minimal air content. The necessary scrapers and air/oil separators to fulfill this requirement require as little space as possible and ought to exhibit a compact configuration.
The present invention solves this problem the oil scrapers are designed as one piece with at least one air/oil separator and are guided to the oil inlet opening of the air/oil separator, at least one oil outlet opening being assigned to at least one air/oil separator in such a manner that in each driving state of a motor vehicle, provided with the internal combustion engine said oil outlet opening is located above an oil level in the oil pan.
The result of the present invention's integral configuration of at least one air/oil separator with the oil scrapers is a very compact type of construction of these two parts, so that they may be integrated into the internal combustion engine without any problems. In addition, the negligible spacing between the air/oil separator and the oil scrapers eliminates the need for a pump, since the oil is scraped off due to the high kinetic energies prevailing in the air/oil separator. Furthermore, to the density difference between air and oil allows the oil to be separated automatically, such an automatic oil separation being the goal. Another advantage of the present invention lies in the feature that no additional channels or the like have to be integrated into the crankcase, thus eliminating any additional casting complexity.
In each driving state of the motor vehicle provided with the internal combustion engine of the invention, at least one oil outlet opening of the air/oil separator is located above the oil level in the oil pan. Thus, the oil is always guaranteed to return to the oil pan without any constraints and without resistance. Preferably all of the oil outlet openings are arranged above the oil level occurring in the oil pan.
If in an advantageous further embodiment of the invention the longitudinal axis of the air/oil separator, around which the oil that is introduced rotates, runs substantially parallel to the crankshaft, then additional space problems are eliminated, because the air/oil separator is usually much larger in the direction of its longitudinal axis than in a plane perpendicular thereto. That is, the air/oil separator is installed in a reclining manner. Yet this feature does not have a negative impact on its function, because the oil does not flow into said air/oil separator due to gravity, but rather due to high centrifugal force.
An especially large amount of oil may be scraped from the crankshaft rotating in the crankcase if each oil scraper is assigned to a connecting rod and each oil scraper has two oil scraping openings arranged one after the other in succession in the crankshaft rotation direction.
Furthermore, a tapering channel may be provided to run from each oil scraping opening to the air/oil separator. Such a tapering channel can increase the oil flow, rate and the oil may thus be guided even faster to the air/oil separator.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.